Once common in the rocky intertidal, these marine mollusks have been affected by overfishing and disease. Thanks to research and conservation, these grazers are making a comeback!
Size frequency on islands
A figure showing the sizes of black abalone across the Channel Islands from 1985 to 2014. Figure credit: Channel Islands National Park.
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Box plots for annual size frequency distributions of black abalone (Haliotis cracherodii) at each island. Blue lines represent mean sizes of H. cracherodii at each island pooled across and sites. Red lines represent the cumulative mean. For more information, consult Figure App.F.13.2 in the CINMS 2016 Condition Report.`
Density & counts on islands
A figure showing the average abundance of black abalone (Haliotis cracherodii) across the Channel Islands from 1985 to 2014 in fixed plots in the rocky intertidal. The inset figure shows actual counts from site-wide searches (1995 to 2014). Figure credit: Channel Islands National Park.
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Black abalone (Haliotis cracherodii) mean density from fixed plots from 1985-2014 (left) and mean counts from site-wide searches from 1995-2014 (inset) at four islands in Channel Islands National Marine Sanctuary. Site wide search counts began in 1995 due to the severe declines in abundance that occurred from 1985-1995. Generally, increasing abundances began approximately in the 2007-2009 timeframe. Error bars were constructed using one standard error from the mean. For more information, consult Figure App.F.13.1 in the CINMS 2016 Condition Report. For more information, consult Figure App.F.13.1 in the CINMS 2016 Condition Report.`